Pregnancy-related heart failure risk is highest postpartum

Women are at the highest risk of heart failure (HF) during the postpartum period, according to a retrospective study from researchers at the University of Illinois at Chicago (UIC).  

Despite comprising less than 2% of all pregnancy-related admissions, about 60% of HF diagnoses related to pregnancy occur during the postpartum period, the researchers discovered. They also found that developing HF during the pregnancy continuum is associated with a wide range of adverse outcomes. Their study appears in Circulation: Heart Failure.

“This finding lends support to using delivery-related hospitalization as a window of opportunity to identify high-risk women and develop surveillance strategies before discharge,” said principal investigator, Mulubrhan Mogos, PhD, assistant professor of nursing at UIC.

For the study, they analyzed more than 50 million pregnancy-related hospitalizations in the US from 2001 to 2011. During this period, there were 7,542 antepartum, 15,620 delivery, and 34,110 postpartum hospitalizations with a diagnosis of HF. The overall prevalence of HF among the study population was 112 cases per 100,000 pregnancy-related hospital discharges.

The postpartum period represented 1.5% of pregnancy-related hospitalizations, but 60% of all pregnancy-related occurrences of HF happened during the postpartum period, followed by those that occurred during the delivery (27%) and antepartum (13%) periods.

A significant 7.1% per year increase in heart failure diagnoses was observed among postpartum hospitalizations from 2001 to 2006, after which the rate stabilized. HF rates during delivery hospitalizations were unchanged.

HF prevalence also increased significantly, by an average of 4.9% annually, among antepartum hospitalizations from 2001 to 2011.

“The increasing trend in HF prevalence during the antepartum period may be attributable, at least in part, to the presence of existing cardiovascular risk factors or conditions among women who become pregnant,” Dr. Mogos and fellow researchers noted.

For example, women with a diagnosis of HF were more likely to be older, black, tobacco and alcohol users, reside in the South and in an area with lower household incomes, and be insured by either Medicare or Medicaid.

Across the pregnancy continuum, women with a diagnosis of HF were substantially more likely to have one or more comorbidities than those without a diagnosis of heart failure.

These researchers also found that adverse outcomes were more likely when women had a diagnosis of HF at any time during the pregnancy continuum. For example, compared with hospitalizations without HF, those with HF were associated with up to a 47-fold increase in the adjusted risk of developing pulmonary edema. The mortality rate increased by 9.8% annually over the study period among women with a diagnosis of HF.

HF was responsible for >9% of inpatient maternal mortality. Delivery-related hospitalizations with a diagnosis of HF were 32 times more likely to result in maternal death before discharge. For women with an HF diagnosis, the risk of mortality increased by about 16-fold during antepartum hospitalizations, and 4-fold during postpartum hospitalizations compared with those without such a diagnosis.

Women are usually discharged from the hospital within 3 days after delivery and traditionally are not evaluated by health care providers again until 6 weeks postpartum.

“At-risk mothers require surveillance during this period, ideally from a multidisciplinary team that includes HF specialists,” the authors advised, adding that “multidisciplinary management of HF has been linked to better outcomes and fewer readmission rates.”